Among the many blue sapphire-producing countries, including Madagascar, Thailand, Burma, Australia, India, Kenya, Tanzania, the United States, and China, Sri Lanka stands out for producing exceptional quality vivid blue sapphires.
Worlds 1 st 2 nd 3 rd largest blue sapphires all are from Sri Lanka. Ceylon blue sapphires are favored across the world due to its naturally forming vivid colour, purity, translucent and density which other countries cannot replicate. The country has the highest density of gems stones compared to land mass than any country in the world.
According to recent confirmations from the gemology institute of Sri Lanka The Star of Adam is the largest blue sapphire certified by the gemological institute. It has surpassed the previous record holder of which had a weight of 1395 carats at a marvelous weight of 1404.49 carats. This blue star sapphire is valued at least $100m and the current owner remaining anonymous estimates that it could sell for up to $175m at auction.
Other exceptional blue sapphires are Giant of the orient of 466 carats found back in 1902 and the Logan Blue sapphire the impeccable of its kind has stunning weight of 423 carats.
Blue sapphires, like other varieties of the corundum family, have the same Mohs hardness of 9 and specific gravity of 4.
Corundum containing repeating structure of aluminum (Al2 ) are colour less. The blue colour difference is due to contamination of titanium and iron. Contamination of Iron only will make the sapphire turn pale yellow.
The process of colour occurrence in the blue sapphire is called the intervalence charge transfer or cooperative transfer. Which means transferring of an electron one transition metal to another. When iron (Fe2+) and (Ti4+) occupies the adjacent sides of the corundum crystal the electron is transferred to form (Fe3+) and (Ti3+). This right amount of titanium and iron combining at adjacent will produce the deep vivid blue.
Although sapphires are found around the globe, not all countries produce the colours that are highly valued. Australia being the dominant producer of sapphires the stones considered to be less valuable due to very dark colour concealing the true beauty of the stone. The distinguishing feature of the Sri Lankan Blue sapphire is the low iron content giving colour and the ability to Florence under ultra violet light. Low iron gives brighter and translucent magnificent colour to the stones. Sapphires originating from the most part of the word inert High iron content typically causing dark blue shades and lower clarity making difficult to identify the intrusions.
Thus the presence of florescence in blue sapphires mostly indicates that the gem stone origin from Sri Lanka. These characteristics enables Sri Lanka to maintain the sparkling reputations among gem producing countries. Out of the 200 minerals that have been classified as precious gemstones 75 are found in abundance in Sri Lanka, making this Small Island to proudly withstand its reputation in global gem and jewelry market.
There are instances where Sri Lankan sapphires shows similarities to that of Madagascar sapphires. This is because of the resemblances rarely found both gem stones. This is mostly due to the geology and composition that makes difficult even for Expert Gem Laboratories to differentiate with accuracy.
Dating back to 900 Million years Sri Lanka, India, and Madagascar belonged to the same supercontinent Rodnia which drifted apart to different continents and subcontinents. There were instances where Madagascar Blue sapphire gets the Sri Lanka origin or otherwise certifications due to traces of elements even by world renowned Laboratories such as GRS, GIA providing geological evidences for early earth history.
The Blue sapphires has its own sub categories principally classified due to colour temperature variance. As shown in the picture.
Cornflower, Peacock, Royal m Velvet blues are the mostly commonly preferred due to their vivid colours. The premium colour categories commanding high prices which are exported to American, European, China Canada, Russia and other Asian countries.
NavyBlue, Indigo and twilight takes the second and other ranks based on the taste of collectors and individuals.
Blue sapphire is typically cut in cushion, round, oval emerald shapes to retain the carats and the colour. Other popular cuts area pears, briolette, hearts and marquises.
Pricing of blue sapphire is differs with the origin where Sri Lanka blue sapphires cherished globally taking places in the engagement ring of Diana and other anonymous elite collectors. Price of blue sapphires is determined by the combination of several factors that includes the origin, colour, size, cut, translucent, purity, and treatment (heat treated or natural). Unheated sapphires with excellent color, cut and clarity are the top of the line and much sought after by gem collectors s due to its rarity. Price can range from $ 200 to $600 for small stones with 1 carat. Price per carat for heat treated for 2 carat gems is doubled with finest stones ranging from $1500 to $2500 per carat. As for those of masterpiece above 5 carat can range $10,000 to $135,000 per carat for exceptionally sized colored pure blue sapphires.
Source: Ceylon Gem Hub
